Estimating the Effects of Climate and Human Activities on Vegetation Coverage in Diverse Ecosystems: A Case Study of the Gansu Section of the Yellow River Basin

Abstract

The Gansu section of the Yellow River Basin (YRB), as an ecologically fragile zone in the upstream YRB, requires a clear understanding of vegetation changes to support effective regional ecological management. However, knowledge of the combined and individual effects of climate and human activities on vegetation coverage in diverse ecosystems remains limited. This study examined the spatiotemporal patterns and underlying driving mechanisms of vegetation growth across diverse ecosystems using the Normalized Difference Vegetation Index (NDVI) from 2000 to 2022. Vegetation growth improved significantly (e.g., an NDVI growth rate of 0.0068 per year), with the proportion of improved areas reaching 91.05% in croplands, 75.06% in forests, and 64.42% in grasslands, while degradation was concentrated on impervious surfaces and barren lands. Human activities were the primary drivers of vegetation restoration, especially with a high contribution in croplands (73.32%), forests (80.12%), and grasslands (67.11%), whereas climate change had a significant impact on wetland improvement (52.03%) and shrubland degradation (61.95%). Among climatic factors, precipitation showed strong positive correlations with NDVI (especially for croplands, grasslands, and wetlands). Conversely, air temperature showed ecosystem-specific impacts, correlating negatively with barren lands but positively with wetlands, shrublands, and croplands. Future NDVI trends exhibited pronounced anti-persistence (e.g., an area of 55.97%), indicating a high risk of vegetation degradation. This study also elucidates the driving effects of ecological projects and agricultural technologies on vegetation recovery, providing a scientific basis for optimizing ecological restoration strategies in the YRB.